An exhaust system usually comprises an exhaust pipe, which carries an exhaust flow away from the internal combustion engine during the operation of the internal combustion engine. Exhaust gas-treating means, for example, particle filters, exhaust mufflers and catalytic converters, may be integrated in this exhaust pipe. Passive exhaust mufflers, which operate, e.g., by means of resonance, absorption, interference and reflection to muffle the air-borne sound being transported in the exhaust pipe, are predominantly used in exhaust mufflers. Contrary hereto, active exhaust mufflers operate with at least one loudspeaker in order to deliberately generate opposing sound. More or less effective extinction of the sound to be muffled is brought about thereby.
Many motor vehicles, especially passenger cars, have a front engine, i.e., an internal combustion engine that is housed in a front-side engine compartment of the vehicle. To make it possible to comply with the noise protection regulations specified for passenger cars, an exhaust system, which operates with passive exhaust mufflers, requires a comparatively great acoustic length. Conventional exhaust systems correspondingly extend from the internal combustion engine arranged on the front side to the rear of the vehicle, where a tail pipe of the exhaust system is located. Exhaust systems for vehicles with front engine, in which the tail pipe is arranged on the side between a front axle and a rear axle of the vehicle, so-called “side pipes,”operate with large-volume exhaust mufflers in order to embody the aforementioned, great acoustic length within the exhaust muffler, e.g., by multiple deflections. Exhaust systems of vehicles with rear engines likewise operate with relatively large-volume exhaust mufflers.
To reduce the energy consumption and pollutant emissions in motor vehicles, it is desirable to make the vehicle more lightweight. Correspondingly, there also are considerations to use active exhaust mufflers, which have a markedly reduced volume as well as markedly reduced weight, instead of the large-volume passive exhaust mufflers. However, the circumstance that the loudspeakers used in the active exhaust mufflers have a comparatively low heat resistance only, which is always below the usual exhaust gas temperatures, is problematic. In principle, active exhaust mufflers in vehicles with front engines can be connected to the exhaust system in the rear area, i.e., quasi as rear mufflers, because the exhaust gases will usually have already cooled sufficiently until the end of such long exhaust systems. A shortening of the exhaust system, which is carried out in order to reduce weight, would have the consequence that the active exhaust muffler would be positioned relatively close to the internal combustion engine. However, the exhaust gases are especially hot close to the engine, which increases the risk of damage to the active exhaust muffler.